BTG2 and breast cancer: Moreover, by analyzing the mutation of prognostic genes in BRCA patients in TCGA-BRCA, it was found that among the copy number variations in 963 BRCA samples, 7 prognostic genes were mutated in a total of 165 samples (17%), of which BTG2 had the highest frequency of mutation in breast cancer, followed by TNFRSF18 and CFB (Figure 8G).